Electric valve circuit



Feb. 20, 1940. M. A. EDWARDS 2,190,775

ELECTRIC VALVE CIRCUIT Filed June 16, 1957 Fi .l. I g r Fig.2. 4

Inventor: Martin A. Edwards,

by W 5:

His ttorney.

Piranha Feb. 20, 1940 Martin A. Edwards, Schenectady, N Y., assignor toGeneral Electric Company, a corporation X I of New York 7 ApplicationJune 16, 1937; Serial No. 148,518

Claims. (01. Est-2n My invention relates to electric valve circuits V land more particularly to control systems for electric valve apparatusemploying ionizable mediums. I

I In the control of electric valve apparatus em- I ploying ionizablemediums, and particularly those having control members of the,immersionignitor type for initiating the arc discharge, it

' has been found that it is highly important to 10 provide controlsystems susceptible of supplying control'voltages of substantiallyperpendicular wave front to effect precise and positive control of theelectric valve apparatus. Furthermore, it

is highly desirable to employ control circuits II which may be energizedfrom commercial sources of alternating voltage and which are simple inconstruction and reliable in operation. More particularly, it has beenfound important to use circuits which apply to the immersion-ignitorcontrol members relatively high voltages of predetermined wave form,preferably of perpendicular wave front, to assure positive initiationofthe .arc discharge at the desired times in the cycle of operation of theelectric valve apparatus.

" Heretofore, the control circuits havenecessitated' the use ofapparatus of inordinate size and rating relative to the amount of energytransmitted by the electric valve apparatus.

It is an object of' my invention to provide a new and improved electricvalve circuit.

It is another object of my invention to provide a new and improvedelectric valve oontrolsys tem for electric valve apparatus of the typeemploying ionizable mediums and control members of the immersion-ignitortype. V

In accordance with the illustrated embodiment of my invention, I providea control circuit for energizing an immersion-ignitor control member ofan electric valve means whereby the electrical discharges are initiatedin a positive and reliable; manner at .accurately determinable instantsin the cycle of operation. More specifically, I provide a-control systemincluding a source of alternating current and a resonant-circuit,

4,5 which may be linear or nonlinear, energized,

from the source of alternating current. A conf trolled electric valve isemployed to impresson the immersion-ignitor control .member aunidirectional voltage of substantially perpendicular wave front derivedfrom one of the elements of the resonant circuit. The controlledelectric valve is provided with a control member which renders theelectric valve conductive at a predetermined time to impress on theimmersion- 56 ignitor control member a voltage of predeterminedmagnitude and wave form. In onemodle fication of my invention, thecontrolled electric valve effects discharge of the capacitance of theresonant circuit to energize the immersion-ignitor control member, andin ancthenmodiflcation of I my invention the controlled electric valveimpresses on the immersion-ignitor control mem-\ her a voltage derivedfrom the inductance in the resonant circuit. n

I For a better understanding of my invention, 30 reference may be had tothe following description, taken in connection with the accompanyingdrawing, and ltsscope will be pointed out in the appended claims. Fig.1, of the drawing diagrammatically shows an embodiment of my inu vvention in which an immerslon-ignitor control member of an electricvalve apparatus is energized by employing a voltage derived from acapacitance of a resonant circuit, and Fig. 2 represents certainoperating. characteristics 39 thereof. Fig. 3 represents-anotherembodiment of my invention in which the immersion-ignitor control memberisenergized in accordancewith a voltage derived from the inductance ofthe resonant circuit. I

, Referring now. to Fig. 1 of the accompanying drawing, my invention isdiagrammatically shown as applied to an electric valve translatingsystemfor transmitting, energy ,from an alternating current circuit I toa direct current circuit, '9

2, through a transformer 3 and electric valve means [and 5. TThetraformer 3 is provided with a primary, winding 6 aving an electricallyintermediate connection 1 and a secondary wind ing 8. Each of theelectric valve means 4 and 5 l5 includes an anode 9, aselfdeconstructing cathode, such as a mercurypool, cathode I0, and. anassociated control member Huwhichmay be of the immersion-ignitor type;The immersionignitor control member ll may be of a material G such asboron-carbide or silicon-carbidaoriof, a material such as that describedand claimed in U. S. Patent 1,822,742 granted to Karl B.McEachronSeptember 8, 1931, and signed to the assignee of the presentapplicatio I provide control circuits l2 and I3 which are associatedwith electric valve means 4 and 5, respectively, to impress onimmersion-ignitor. control members H thereof unidirectional voltages ofsubstantially perpendicularwave frontfl fi Each of the control circuitsl2 and I3 includes a resonant circuit, which may be either linear ornonlinear, and comprises an inductance, which may or may not beself-saturating, and a capacitance 15 which, as illustrated, areconnected in II and a variable resistance l9.- One terminal of thealternating current circuit 16 is connected to the electricallyintermediate terminal 1 of primary winding 6 of transformer 3.Considering circuit 52, a suitable unidirectional conducting device,such as an electric valve 20, is connected between a point of theresonant circuit and cathode iii to impress on immersion-ignitor controlmember H a voltage derived from one of the elements of the resonantcircuit, as, for example, the voltage appearing across the terminals ofcapacitance 15. The electric valve 20 is preferably oi the typeemploying an ionizable medium, such as a gas or a vapor, and includes ananode a cathode and a control member 23. An inductance 2:3 is connectedin series relation with .thecontrol member ii. cathode IQ and electricvalveid to extendfin the direction of the. time the current transmittedto the control memher it when the electric valve 20 .efiects dischargeor" the capacitance 35. The feature of the arrangement of Fig. 1,whereby a resonant cirand a unidirectional conducting device areemployed to energize a control member of an electric valve, is disclosedin my copending application Serial No. 148,517, filed June 16, 1937, andassigned to the assignee of the present application.

To obtain a control voltage to render electric valve 28 conductive andto effect energization of immersion-ignitor control member ll ofelectric valve 4 at a predetermined time in the cycle of voltage appliedto anode 9, I provide a suitable phase shifting circuit such as aseriallyconnected capacitance 25 and a resistance 26 which are connected.to the source of alternating current 56. A suitable current limitingresistance '2? may be connected in series relation with thecontrelmember 23 of electric valve 20.

The operation of the embodiment of my invention shown in Fig. 1 will beconsidered when the system is operating to transmit unidirec-.

tional current to the load'circuit 2 from the alternating currentcircuit 1,. through transformer 3 and electric valve means 4 and5. Aswill be well understood by those skilled in the art, the electric valves5 and 5 will-be rendered conductive by the control circuits l2 and .I3and will conduct current alternately to transmit unidirectional currentto load circuit 2. Adjustable resistance ll! of phase shifting circuiti! is adjusted to impress on the resonant circuit, including inductanceI l and the capacitance IS, an alternating voltage having apredeterminedphase displacementrelative to the voltage impressed on anodes 9 ofelectric valve means 4 and 5. Inductance i l and capacitance I 5,0perateas a resonant circuit tuned to the frequency of the alternating currentcircuit l6. Under these conditions, it is to be understood that thevoltages appearing across the inductance l4 andcapacitance i5 rise tovalues several times that applied to the resonant circuit, and thesevoltages are employed to impress on the control members ll voltageswhich assure positive initiation of the arc discharges.

The operating characteristics represented in Fig. 2 may be considered tofacilitate the explanation of the operation or the control circuits l2and 13 of the arrangement of Fig. 1. Curve A may represent the'voltageappearing across the terminals of capacitance IS in circuit I2. Theelectric valve 20 is energized by the excitation circuit therefor to berendered conductive at a time ato impress on control member H aunidirectional voltage of substantially perpen- V valve 20 is renderedconductive, the resonant circult will be unbalanced, that is,rendereddissonant thereby limiting the current transmitted to thecircuit l2 from the source of alternating current 18.

- It is to be understood that, by the proper design and proportioning oithe self-saturating inductance H, the resonant circuit may be made tooperate as a non-linear resonant circuit.

Under this condition of operation, the voltage' appearing across thecapacitance IE will be one of rectangular wave form having asubstantially perpendicular wave front, and the voltage appearing acrossthe self-saturating inductance l4 .will be of substantially peaked waveform. It

is to be understood that my invention in its broader aspects applies tothe control circuit when it: is operating either as a linear resonantcircuit or as anonlinear resonant circuit.

, The arrangement of my invention diagrammatically shown in Fig. 3 issubstantially the same as that shown in Fig. 1 and correspondingelements have been assigned like reference numerals. In the arrangementof Fig. 3, the immersion-ignitor control member H is energized inaccordance with the voltage appearing across the inductance l4. Theresonant circuit, including inductance and capacitance l5, may bearranged to operate either as a linear resonant circuit or as anonlinear resonant circuit. The

inductance l4 may be designed to be self-saturating.

The operation 0! the arrangement of. Fig. 3

' is substantially the same as that of Fig. 1. The

, age appearing across the inductance l4 will, of

course, be sinusoidal and the electric valve 20 may be renderedconductive at about the maximum value of applied voltage to impress onthe control member H a relatively large voltage of steep wave front.When the circuit is operating as a nonlinear circuit, the voltageappearing across the terminals of inductance will be of peaked wave formand the electric valve 20 may be rendered conductive at substantiallythe peak value of this voltage to impress a commanding voltage on thecontrol member II. a

One of the principal advantages or the convoltage. During the next halfcycle of applied voltage 01 the same polarity, thecircuit willautomatically' increase its voltage due to the resonating condition ofthe circuit, assuring ignition of the arc during that half, cycle. Thedirection of change or voltage under these conditions tends to cause theelectric valve 4 to be rendered conductive. Another important feature ofmy invention is thefeature of the control circuits by virtue of whichrelatively large currents are supplied to the control members I Iwithout imposing on the supply circuit, such as supply circuit l orcircuit l6, heavy current conditions. This feature is of particularimportance where it is desired to effect positive control by supplyingrelatively large currents to the control members, and where it isundesirable to obtain these currents directly from the supply circuit.

While I have shown and described my inven: tion as applied to aparticular system 01 connections and as embodying various devicesdiagrammatically shown, it will be obvious to those skilled in the artthat changes and modifications may be made without departing from myinvention, and I, therefore, aim in the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeof my invention. L

What I claim as new and desire to Letters Patent or the United Statesis:

1. In combination, an electric valve means having ,a control member, asource of alternating current, a resonant circuit connected to beenergized continuously from said source for producing a voltagesubstantially greater than that applied to said resonant circuit, andmeans for impressing on said control member a component of voltagederived from said resonant circuit and for rendering said electric valvemeans conductive during hali' cycles of voltage of predeterminedpolarity of said source and'comprising a controlled electric valveconnected between said resonant circuit and said control member, saidresosecu're by ,nant circuit serving to-increase said component ofvoltage accumulatively in the event said controlled electric valve failsto conduct current to said control member during each half cycle ofvoltage of said predetermined'polarity.

2. In combination, an electric valve means having a control member, asource of alternating current, a resonant circuit connected to beenergized continuously from said source and including an inductiveimpedance and a capacitive impedance for producing voltagessubstantially greater than the voltage applied to said resonant circuit,and means comprising a controlled electric valve for impressing on saidcontrol member a voltage derived from one of said impedances and forrendering selectively resonant and dissonant said resonant circuit, saidresonant circuit serving to increase said component of voltage in theevent said controlled electric valve fails to conduct cur-- rent to saidcontrol member during each half cycle of voltage of predeterminedpolarity of said source.

3. In combination, an electric valve means employing an ionizable mediumhaving a control member for initiating an arc discharge, a source ofalternating current, a resonant circuit con nected to be energizedcontinuously from said source and including a serially-connectedinductance and a capacitance for producing a voltage substantiallygreater than the voltage applied to said resonant circuit, and acontrolled electric valve connected to impress on said control memher acomponent of voltage derived from said capacitance to render saidelectric valve means conductive during each half cycle of voltage ofpredetermined polarity of said source and for rendering said resonantcircuit dissonant when in a conducting condition. a

4. In combination, an electric valve means having a control member, asource of alternating current, a resonant circuit continuously energizedfrom said source and including a serially-connected capacitance and aninductance for producing a voltage substantiallygreater than the voltageapplied to said resonant circuit, an electric valve having a controlmember and being connected to energize said first mentioned controlmember in accordance with a component of yolta age, derived from saidresonant circuitfljand nected capacitance and an inductance forproducing a voltage substantially greater than the voltage appliedtosaid resonant circuit, an electric valve having a control member andbeing connected to energize said first mentioned control member inaccordance with the voltage appearing across said capacitance and torender said resonant circuit selectively resonant or dissonant, andmeans for energizing said control member of said electric valve torender said valve conductive when the voltage appearing across saidcapacitance attains a predetermined value thereby rendering saidelectric valve means conductive. i

6. In combination, an alternating current circuit, electric valve meansconnected to be energized from said circuit and having an anode, acathode and a control member, a source of alter nating voltage having apredetermined pha se displacement relative to the voltage of saidalternating current circuit, a resonant circuit connected to beenergized continuously from said source and comprising aserially-connected capacitance and an inductance for producing a voltagesubstantially greater thanthe voltage applied to said resonant circuit,an electric valve connected to energize said control member bydischarging said capacitance through said control member therebyrendering said resonant circuit dissonant, and means for rendering saidelectric valve conductive at the maximum instantaneous value of voltageduring each cycle.

7. In combination, an alternating current 'circuit, an electric valvemeans connected to be energized from said circuit and including ananode, a cathode and an immersion-ignitor control member associated withsaid cathode, a

mined :phase displacement relative to the voltage cuit dissonant, saidelectric -valve having a con-- trol member and said resonant circuitserving to effect an accumulative increase in the voltage derived fromsaid capacitance or said inductance in the event said electricvalve'fails to conduct current to said control member during each halfcycle of voltage of predetermined polarity, and a phase shifting circuitfor energizing said last mentioned control member to render saidelectric vvalve conductive to effect energization of saidimmers'ion-ignitor control member at the maximum instantaneous value ofvoltage during each :cycle.

8. In combination, an electric valve means having a control member, asource of alternating current, a nonlinear resonant circuit connected tobe energized-continuously from said source and including aserially-connected capacitance and a self-saturating inductance forproducing a voltage substantially greater than the voltage applied tosaid resonant circuit, and means comprising an electric valve forimpressing onsaid control member a component of voltage derived fromsaid resonant circuit and to render said resonant circuit dissonant whenin a conducting condition.

9. In combination, an electric valve means having a control member, asource of alternating current, anonlinear resonant circuit connected tobe energized continuously from said source and including aserially-connected capacitance'and a self-saturating inductance forproducing a voltage substantially greater than the voltage applied tosaid resonant circuit, and means comprising an electric valve forimpressing on saidcontrol member a component of voltage of.perpendicular wave front derived. from said inductance and to rendersaid resonantcircuit dissonant when said second mentioned electricvalveis in a conducting condition.

10. In combination, an electric valve means having a control member, asource oi! alternating current,a resonant circuit continuously energized,from said source and including a serially-connected capacitance and aninductance for producing a voltage substantially greater than thevoltage applied to said resonant circuit, an electric valve having acontrol member and being connected to energize said first mentionedcontrol a member in accordance with a component of voltagederived fromsaid resonant circuit, said resonant circuit serving to increaseaccumulatively the voltage derived from said resonant circuit in theevent said electric valve fails to conduct cur-' rent to said controlmember during each half cycle of voltage or predetermined polarity ofsaid source and means comprising a phase shifting circuit for energizingsaid control member of said electric valve to render said electric valveconduc-v tive at a predetermined time durlng each .cycle of voltage ofsaid source. 7

.MAR N A; EDWARDS.

